A digital camera generates digital images of a subject according to image signals from an image sensor (CCD or the like) which has received light from the image of the subject through an optical photographic system. In recent years, one having a blur correction to correct blurs due to camera shake at shooting has been widely spread.
For example, Japanese Laid-open Patent Application Publication No. 2004-274242 discloses a blur correction mechanism in a digital camera in which the image sensor (CCD or the like) is moved in accordance with a blur amount of a subject image caused by camera shake in a plane (X to Y plane) perpendicular to the optical axis direction of the optical photographic system.
Such a blur correction mechanism has a frame member on which the image sensor is arranged, and movably disposed in two directions (X to Y direction) orthogonal to each other and perpendicular to the optical axis direction. It corrects blurs in images by moving the frame member in accordance with a blur amount of a subject image to move the image sensor in a plane perpendicular to the optical axis direction.
However, this blur correction mechanism has a problem that since the moving of the frame member is controlled by supplying power to a driver (such as motor, piezo element) connected thereto, the power-off of the driver releases the blur correction function and makes the frame member freely movable, causing the center position of the image sensor on the frame member to be shifted from the optical axis due to disturbance such as gravity.
In order to prevent this problem, it is possible to supply power to the driver during the release of the blur correction for the purpose of controlling the center position of the image sensor on the frame member. However, this leads to another problem of extraneous power consumption.
In view of solving the above problems, the inventor of the present application has proposed an imaging apparatus which comprises a forcible original position retainer unit mechanically retaining a center position (original position) of the image sensor on the optical axis while the blur correction is turned off (disclosed in Japanese Laid-open Patent Application Publication No. 2005-305841, paragraph [0097], FIGS. 9, 12(a)). The forcible original position retainer unit includes a stepping motor (STM1), and a forcible holding plate (26) having a holding pin (33) attached to its end and reciprocatable in the optical axis direction by driving the stepping motor. In this imaging apparatus, the center position of the image sensor can be mechanically maintained on the optical axis during the turning-off of the blur correction by engaging a concave portion (19a) in the image sensor with the holding pin. Thus, the image sensor can be retained so that the center position thereof is positioned on the optical axis even during the turning-off of the driver for blur correction.